Make columns resizable

[SanderMertens]

Issue
Currently the explorer layout is not resizable in the way that the v3 explorer was.

Solution
Make columns resizable for the following pages:

• Entities (tree icon)
• Queries (search icon)

Example
https://github.com/user-attachments/assets/77b02973-2f5a-404a-b9aa-bbdd5b4917c4

[SanderMertens]

@addbounty $250

[addbounty]

Make a Draft PR early so others can see you are working on it! To automatically create one:

# Using npx (installed if you have NodeJS/npm)
npx bountybot start flecs-hub/explorer#41

# Or, use cargo (installed if you have Rust)
cargo install bounty
bounty start flecs-hub/explorer#41

When merged, you will receive the bounty!

[maxomatic458]

@ryanhcode are you still working on this?

[ryanhcode]

@maxomatic458 yes! I've posted about it in the flecs discord. Will likely finish up the PR in the next day or two.